This invention relates to the electrode structure of a high frequency hyperthermia device which is inserted into an oral cavity to treat a cancer tissue or the like in its narrow part by heating it with high frequency electric field.
FIG. 8(A) shows one example of a conventional high frequency hyperthermia device's electrode structure which is inserted into a body cavity.
The electrode structure, or an applicator comprising an electrode and a solution containing bag, comprises: a elongated flexible pipe 71; an electrode 72 built in one end portion of the flexible pipe 71; a cooling solution containing bag 72a combined suitably with the electrode 72; and a two-prongs-fork-shaped cooling solution circulating mouth 73 at the other end portion which is used to circulate a cooling solution to the solution containing bag 72a. The electrode structure further comprises: an electrode lead wire 74 led out of the pipe 71 so that the electrode 72 is connected to a high frequency electric source through it.
As shown in FIG. 8(B), the applicator is inserted into the body cavity until the front electrode 72 (with the solution containing bag 72a) confronts with the cancer tissue. An ordinary portable applicator 75 (comprising an electrode and a solution containing bag) is placed on the skin of the organism (human body) A in such a manner that the cancer tissue is located between the electrode 72 and the portable applicator 75. Under this condition, a high frequency electric field is applied between the two electrodes, to heat the cancer tissue.
In the above-described electrode structure, the electrode is integral with the solution containing bag. Therefore, if the solution containing bag is broken, then the applicator itself can be no longer used. On the other hand, in order to treat the cancer tissue formed at a complicated part, such as the body cavity, of the body, it is necessary to provide a solution containing bag which is suitable for a part to be treated (such as the bottom of the body cavity, the tongue, or the rear side of the tongue). In order to satisfy this requirement, since in the conventional applicator, the electrode is integral with the solution containing bag, it is necessary to provide a variety of applicators different in structure. Furthermore, in the conventional electrode structure, the electrode is provided at the end of the flexible pipe, and accordingly it is difficult to fixedly hold the electrode which is inserted into the body cavity and confronted with the diseased part. In this case, heretofore, the tongue of the patient is utilized to fixedly hold the electrode. This method will cause the patient a pain, and at worst burn the tongue with the hot electrode.
Furthermore, in the case where the diseased part is treated by heating it with the electrode structure, it is essential to allow the electrode to suitably confront with the diseased part (cancer tissue). However, since, in this case, the electrode is inserted into the body cavity, it is impossible to observe the electrode from outside; that is, it is impossible to determine whether or not the electrode is correctly confronted with the diseased part. Therefore, heretofore the following two methods are employed to detect the position of the electrode inserted into the body cavity: In the first method, as shown in FIG. 8(A), a measure 85 is provided for the pipe 71, so that, when the electrode is inserted into the body cavity, its depth is detected by reading the measure 85: that is, the first method is of a visual system. In the second method, as shown in FIG. 9, a line 86 is formed on the pipe 71 by coating it with an X-ray contrast medium, so that the position of the electrode 72 is detected through X-rays. That is, the second method is of an X-ray system.
However, the two methods are disadvantageous in the following points: as shown in FIG. 10. That is, the first method suffers from the following difficulty: In the case where the body cavity has a bent part as in the case of the stomach, the pipe 71 inserted into it is bent there, and accordingly it is difficult to determine the depth of the electrode 72 correctly. In the case of the second method of X-ray system, the electrode 72 is inserted into the patient in the room where the X-ray device is installed (i.e., in the room which is different from the treating room, and the position of the electrode 72 is confirmed through X-rays. Under this condition, the patient is moved back to the treating room. This will cause the patient great pain.